Research project DI/06 (Research action DI)
In the frame of phase 1 of the digitization plan of the Federal Scientific Institutes and the Royal Belgian Film Archive initialized by the Belgian Science Policy (BELSPO), the Royal Meteorological Institute of Belgium (RMIB) and the Belgian Institute of Space Aeronomy (BISA) have proposed a common project for the digitization of ancient observation data. The objective was the conservation in numerical form of time series, with great scientific interest, which were at that moment only available under written format or under a difficult scientifically exploitable format in the archives of both institutes.
The choice of the digitization procedure was to be done by the manual encoding of series of observations chosen as a priority by the RMIB and the BISA. After a first intern, preliminary preparatory phase of the encoding work, two technical encoders were engaged to attain the retained priorities.
Before the start of the project, the RMIB disposed of numerical values of daily observations of temperature extremes (maximum and minimum) and the precipitation quantities carried out since the beginning of the years 1950 by the observers of the Belgian climatological network. Before that date, only some long rainfall series were already encoded by the section of Hydrology of the Institute at the beginning of the years 1980. Phase 1 of the digitization plan proved to be the occasion to extend the encoding of daily climatological data over the period 1881–1949 using and exploiting the monthly written bulletins available in the archive of the Institute.
All the existing temperature data over the considered period were numerated and a choice of rainfall stations was made to make sure that the encoding remained within the desired delays. In total, the data of 623 pluviometrical stations and 239 temperature stations were taken into account. More than 4,8 million daily climatological data were saved under numerical format; today these raw data are available in the Oracle database of the RMIB.
The project of saving the daily climatological data is the first necessary and preliminary step with regard to the study of regional climate changes in Belgium since the end of the 19th century. Before attaining that objective, a second equally important step is still necessary. We now have to study the data for their quality and we have to determine their homogeneity.
The BISA is a younger scientific institute than the RMIB, founded from it in the years 1960 with the aim to develop the sciences of the atmosphere. The Institute disposes of relatively small ancient archives which where indispensable to be saved under numerical format. Nevertheless, a whole of observations of great scientific interest were retained for digitization through manual encoding in the frame of phase 1 of the digitization plan. The considered data were the ozone observations carried out in Antarctica between 1965 and 1967 at the Roi Baudouin base by means of the Dobson n° 54 instrument. At that time these data were collected during a common Belgo-Dutch expedition. The original data available in observation sheets from the observers were discovered in the KNMI (De Bilt) archives in 1989 and consequently these data were digitized. The digitization includes all the data, even those which were eliminated by the observers due to the difficulties of the measurement technique. The conservation of these ozone data is assured by a secured server of the BISA. They are accessible through the link http://ozonehistory.aeronomie.be/history.htm
A first analysis confirmed the differences reported at that time between the ozone values of November 1965 and 1966 and demonstrated that the observers did not systematically ignore low ozone values during the month of October. The present means allow to give a new life to these results by the comparison with global circulation models and to develop techniques for a future retreatment of the entirety of the Dobson instrument archives.
Banque de données d’observations climatologiques manuscrites (Phase 1) : rapport final
Tricot, Christian - Muller, Christian - Mormal, Pascal ... et al Bruxelles : Politique Scientifique fédérale, 2012 (SP2521)
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